Morgan Stanley Discovery Portfolio Investment Risks - Morgan Stanley Discovery Portfolio	Dec. 31, 2025
Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Market Risk. The Portfolio’s share price can fall because of, among other things, a decline in the market as a whole, deterioration in the prospects for a particular industry or company, changes in general economic conditions, such as prevailing interest rates or investor sentiment, or other factors including terrorism, war, natural disasters and the spread of infectious illness including epidemics or pandemics. In addition, unexpected political, regulatory, trade and diplomatic events within the United States and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy, perhaps suddenly and to a significant degree. Significant disruptions to the financial markets could adversely affect the liquidity and volatility of securities held by the Portfolio.
Foreign Investment Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Foreign Investment Risk. Investments in foreign securities, whether direct or indirect, tend to be more volatile and less liquid than investments in U.S. securities because, among other things, they involve risks relating to political, social, economic and other developments abroad, as well as risks resulting from differences between the regulations and reporting standards and practices to which U.S. and foreign issuers are subject. To the extent foreign securities are denominated in foreign currencies, their values may be adversely affected by changes in currency exchange rates. All of the risks of investing in foreign securities are typically increased by investing in emerging market countries.
Market Capitalization Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Market Capitalization Risk. Investing primarily in issuers in one market capitalization category (large, medium or small) carries the risk that due to current market conditions that category will be out of favor with investors. Larger, more established companies may be unable to respond quickly to new competitive challenges or attain the high growth rate of successful smaller companies. Stocks of medium and small capitalization companies may be more volatile than those of larger companies due to, among other things, narrower product lines, more limited financial resources and fewer experienced managers. In addition, there is typically less publicly available information about small capitalization companies, and their stocks may have a more limited trading market than stocks of larger companies.
Investment Style Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment Style Risk. Different investment styles such as growth or value tend to shift in and out of favor, depending on market and economic conditions as well as investor sentiment. The Portfolio may outperform or underperform other funds that employ a different investment style.
Derivatives Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Derivatives Risk. The Portfolio may invest in derivatives to obtain investment exposure, enhance return or “hedge” or protect its assets from an unfavorable shift in the value or rate of a reference instrument or asset. Derivatives can be highly volatile and can significantly increase the Portfolio’s exposure to market risk, credit and counterparty risk (the risk that a counterparty will default or become less creditworthy) and other risks. Derivatives may be illiquid and difficult to value and can involve risks in addition to, and potentially greater than, the risks of the underlying reference instrument. Because of their complex nature, some derivatives may not perform as intended. As a result, the Portfolio may not realize the anticipated benefits from a derivative it holds or it may realize losses. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Derivative transactions may create investment leverage, which increases the Portfolio’s volatility and may require the Portfolio to liquidate portfolio securities when it is not advantageous to do so. Government regulation of derivative instruments may limit or prevent the Portfolio from using such instruments as part of its investment strategies, which could adversely affect the Portfolio.
Focused Investment Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Focused Investment Risk. Substantial investments in a relatively small number of securities or issuers, or a particular market, industry, group of industries, country, region, group of countries, asset class or sector make the Portfolio’s performance more susceptible to any single economic, market, political or regulatory occurrence affecting those particular securities or issuers or that particular market, industry, group of industries, country, region, group of countries, asset class or sector than a portfolio that invests more broadly.
Rule 144A and Other Exempted Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Rule 144A and Other Exempted Securities Risk. In the U.S. market, private placements may typically be sold only to qualified institutional buyers, or qualified purchasers, as applicable. If an insufficient number of eligible buyers is interested in purchasing privately placed and other securities or instruments exempt from Securities and Exchange Commission registration (collectively “private placements”) at a particular time, this could adversely affect the marketability of such investments and the Portfolio might be unable to dispose of them promptly or at reasonable prices, subjecting the Portfolio to liquidity risk. Even the Portfolio’s holdings of liquid private placements may increase the level of Portfolio illiquidity if eligible buyers are unable or unwilling to purchase them at a particular time. The information that issuers of Rule 144A eligible securities are required to disclose to potential investors is much less extensive than that required of public companies and is not publicly available, and issuers of Rule 144A eligible securities can require recipients of the offering information (such as the Portfolio) to agree contractually to keep the information confidential, which could also adversely affect the Portfolio’s ability to dispose of the security.
Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	You could lose money by investing in the Portfolio.
Risk Not Insured Depository Institution [Member]
Prospectus [Line Items]
Risk [Text Block]	An investment in the Portfolio through a Contract is not a deposit or obligation of, or guaranteed by, any bank, and is not federally insured by the Federal Deposit Insurance Corporation, the Federal Reserve Board, or any other agency of the U.S. Government.

Morgan Stanley Discovery Portfolio Investment Risks - Morgan Stanley Discovery Portfolio

Dec. 31, 2025

Market Risk. The Portfolio’s share price can fall because of, among other things, a decline in the market as a whole, deterioration in the prospects for a particular industry or company, changes in general economic conditions, such as prevailing interest rates or investor sentiment, or other factors including terrorism, war, natural disasters and the spread of infectious illness including epidemics or pandemics. In addition, unexpected political, regulatory, trade and diplomatic events within the United States and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy, perhaps suddenly and to a significant degree. Significant disruptions to the financial markets could adversely affect the liquidity and volatility of securities held by the Portfolio.

Prospectus [Line Items]

Risk [Text Block]

Foreign Investment Risk. Investments in foreign securities, whether direct or indirect, tend to be more volatile and less liquid than investments in U.S. securities because, among other things, they involve risks relating to political, social, economic and other developments abroad, as well as risks resulting from differences between the regulations and reporting standards and practices to which U.S. and foreign issuers are subject. To the extent foreign securities are denominated in foreign currencies, their values may be adversely affected by changes in currency exchange rates. All of the risks of investing in foreign securities are typically increased by investing in emerging market countries.

Market Capitalization Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

Market Capitalization Risk. Investing primarily in issuers in one market capitalization category (large, medium or small) carries the risk that due to current market conditions that category will be out of favor with investors. Larger, more established companies may be unable to respond quickly to new competitive challenges or attain the high growth rate of successful smaller companies. Stocks of medium and small capitalization companies may be more volatile than those of larger companies due to, among other things, narrower product lines, more limited financial resources and fewer experienced managers. In addition, there is typically less publicly available information about small capitalization companies, and their stocks may have a more limited trading market than stocks of larger companies.

Investment Style Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

Investment Style Risk. Different investment styles such as growth or value tend to shift in and out of favor, depending on market and economic conditions as well as investor sentiment. The Portfolio may outperform or underperform other funds that employ a different investment style.

Derivatives Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

Derivatives Risk. The Portfolio may invest in derivatives to obtain investment exposure, enhance return or “hedge” or protect its assets from an unfavorable shift in the value or rate of a reference instrument or asset. Derivatives can be highly volatile and can significantly increase the Portfolio’s exposure to market risk, credit and counterparty risk (the risk that a counterparty will default or become less creditworthy) and other risks. Derivatives may be illiquid and difficult to value and can involve risks in addition to, and potentially greater than, the risks of the underlying reference instrument. Because of their complex nature, some derivatives may not perform as intended. As a result, the Portfolio may not realize the anticipated benefits from a derivative it holds or it may realize losses. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. Derivative transactions may create investment leverage, which increases the Portfolio’s volatility and may require the Portfolio to liquidate portfolio securities when it is not advantageous to do so. Government regulation of derivative instruments may limit or prevent the Portfolio from using such instruments as part of its investment strategies, which could adversely affect the Portfolio.

Focused Investment Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

Focused Investment Risk. Substantial investments in a relatively small number of securities or issuers, or a particular market, industry, group of industries, country, region, group of countries, asset class or sector make the Portfolio’s performance more susceptible to any single economic, market, political or regulatory occurrence affecting those particular securities or issuers or that particular market, industry, group of industries, country, region, group of countries, asset class or sector than a portfolio that invests more broadly.

Rule 144A and Other Exempted Securities Risk [Member]

Prospectus [Line Items]

Risk [Text Block]

Rule 144A and Other Exempted Securities Risk. In the U.S. market, private placements may typically be sold only to qualified institutional buyers, or qualified purchasers, as applicable. If an insufficient number of eligible buyers is interested in purchasing privately placed and other securities or instruments exempt from Securities and Exchange Commission registration (collectively “private placements”) at a particular time, this could adversely affect the marketability of such investments and the Portfolio might be unable to dispose of them promptly or at reasonable prices, subjecting the Portfolio to liquidity risk. Even the Portfolio’s holdings of liquid private placements may increase the level of Portfolio illiquidity if eligible buyers are unable or unwilling to purchase them at a particular time. The information that issuers of Rule 144A eligible securities are required to disclose to potential investors is much less extensive than that required of public companies and is not publicly available, and issuers of Rule 144A eligible securities can require recipients of the offering information (such as the Portfolio) to agree contractually to keep the information confidential, which could also adversely affect the Portfolio’s ability to dispose of the security.

Risk Lose Money [Member]

Prospectus [Line Items]

Risk [Text Block]

You could lose money by investing in the Portfolio.

Risk Not Insured Depository Institution [Member]

Prospectus [Line Items]

Risk [Text Block]

An investment in the Portfolio through a Contract is not a deposit or obligation of, or guaranteed by, any bank, and is not federally insured by the Federal Deposit Insurance Corporation, the Federal Reserve Board, or any other agency of the U.S. Government.